 /*******************************************************************************
  * Copyright (c) 2006 IBM Corporation and others.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
  * http://www.eclipse.org/legal/epl-v10.html
  *
  * Contributors:
  * IBM Corporation - initial API and implementation
  *******************************************************************************/
 package org.eclipse.core.runtime.internal.adaptor;

 import java.io.File ;
 import java.net.MalformedURLException ;
 import java.net.URL ;

 /**
  * @since 3.3
  */
 public class LocationHelper {
     /**
      * Builds a URL with the given specification
      * @param spec the URL specification
      * @param trailingSlash flag to indicate a trailing slash on the spec
      * @return a URL
      */
     public static URL buildURL(String spec, boolean trailingSlash) {
         if (spec == null)
             return null;
         boolean isFile = spec.startsWith("file:"); //$NON-NLS-1$
 try {
             if (isFile)
                 return adjustTrailingSlash(new File (spec.substring(5)).toURL(), trailingSlash);
             return new URL (spec);
         } catch (MalformedURLException e) {
             // if we failed and it is a file spec, there is nothing more we can do
 // otherwise, try to make the spec into a file URL.
 if (isFile)
                 return null;
             try {
                 return adjustTrailingSlash(new File (spec).toURL(), trailingSlash);
             } catch (MalformedURLException e1) {
                 return null;
             }
         }
     }

     private static URL adjustTrailingSlash(URL url, boolean trailingSlash) throws MalformedURLException {
         String file = url.getFile();
         if (trailingSlash == (file.endsWith("/"))) //$NON-NLS-1$
 return url;
         file = trailingSlash ? file + "/" : file.substring(0, file.length() - 1); //$NON-NLS-1$
 return new URL (url.getProtocol(), url.getHost(), file);
     }

 }

